Influence of three microbial feed additives of Megasphaera elsdenii, Saccharomyces cerevisiae and Lactobacillus sp. on ruminal methane and carbon dioxide production, and biofermentation kinetics.

AIMS: This study was performed to investigate the effects of Megasphaera elsdenii (Me), Saccharomyces cerevisiae (SC) and lactic acid bacteria (FP-Lactobacillus fermentum plus Lactobacillus plantarum) alone or in combination on biogas production and ruminal biofermentation parameter in a heterofermenter system.

METHODS AND RESULTS: Eight treatments were evaluated; (i) control (without additive; CON); (ii) Me; (iii) SC; (iv) FP; (v) Me plus SC (MSC); (vi) Me plus FP (MFP); (vii) SC plus FP (SCFP) and (viii) Me plus SC plus FP (MSCFP). Doses of FP, Me and SC were 1·5 × 108 (CFU per ml), 1·5 × 108 (CFU per ml) and 1·4 × 107 (CFU 0·002-1  g), respectively. Biogas production in all time increased (P < 0·05) by MSCFP than CON additive. The proportional methane (CH4 ) decreased (P < 0·05) in MSCFP and FP, while carbon dioxide (CO2 ) was decreased (P < 0·05) by SC compared MSCFP and MSC. The proportional CO2 decreased (P < 0·05) by MSCFP and FP additive. The mean concentration of NH3 -N was not affected by treatments. Concentration of total volatile fatty acids and the percent of acetate and propionate was not affected by treatments. The highest (P < 0·05) percent of butyrate and valerate were observed in MSCFP additive. The experiment showed that microbial additives of FP, SCFP and MSCFP reduced proportional CH4 and CO2 .

CONCLUSIONS: Microbial additives of MFP and MSCFP had a sustainable positive efficiency on pH and volatile fatty acids and mitigate CH4 and CO2 .

SIGNIFICANCE AND IMPACT OF THE STUDY: The use of microbial additives control on the ruminal pH (MFP) and improve VFA such as butyrate (MSC, MSCFP) and valerate (MSCFP) and reduce the greenhouse gases production showed a reduced risk of ruminal acidosis.